This invention relates to an automatic planing control system for motor boats equipped with outboard motors. The control keeps the outboard motor propeller axis parallel with the surface of the water, or at a predetermined angle, wherever possible when the motor boat is running at a constant speed or being accelerated. Also the planing control protects the outboard motor at the down-blow state. This invention also relates to an FET bridge protection circuit in the automatic planing control system for setting the propeller of the outboard motor at a predetermined angle.
In the present Specification, the word planing means to lift partly the boat body out of the water to an appropriate degree, rather than bringing the boat body to the state of hump.